The present invention relates to telephone services, and more particularly to a method and device for providing intermediate telephone call notification services while increasing the reliability of voice mail service.
Telephone network based voice mail allows callers to leave voice messages when a telephone subscriber is unavailable, resulting from a busy subscriber line, or from a subscriber not answering a ringing line. Typically, voice-mail service is implemented by one or more voice mail servers (xe2x80x9cVMSxe2x80x9ds) that are physically separate from the telephone subscriber""s central office switch (xe2x80x9cCOxe2x80x9d). When the subscriber is unavailable, the CO executes an appropriate forwarding feature to connect a caller to the proper VMS allowing the caller to leave a voice mail message for later listening by the subscriber. If the subscriber does not answer, the known CO call forward no answer (xe2x80x9cCFNAxe2x80x9d) feature forwards the incoming call to the VMS. Similarly, if the subscriber line is busy, the CO call forward busy line (xe2x80x9cCFBLxe2x80x9d) feature causes the CO to forward the call to the VMS.
As understood by those skilled in the art, COs supporting the CFNA/CFBL features allow an administrator to associate alternate telephone dial numbers (xe2x80x9cDNxe2x80x9ds) for each subscriber DN. The CO forwards calls directed to the subscriber DN in the event the subscriber line is busy or is not answered.
Recently, various other enhanced telephony services in addition to network-based voice mail have become available. These services are referred to as xe2x80x9cintermediate servicesxe2x80x9d and are often also provided by stand-alone servers that are physically separate from both the CO and the VMSs. These intermediate services are typically provided after a call has been forwarded to a CO, and prior to ultimate call disposal, to, for example, a VMS. Usually these intermediate services rely on either the CFNA or CFBL features. Using these features, calls are transferred to a DN associated with an intermediate service server. Ultimately a call processed by an intermediate server may be transferred to a VMS by the intermediate service server for subscribers that subscribe to both the intermediate service and VMS service. The intermediate server typically maintains a database and uses the database to forward the call to the appropriate VMS. In this sense, the service assumes an intermediate role between the CO and the VMS.
Intermediate services typically provide a notification of an incoming call, that may be received by a subscriber or may be further processed. An example of an intermediate service is Internet Call Waiting (xe2x80x9cICWxe2x80x9d) service, as disclosed in U.S. patent application Ser. No. 08/911,036, the contents of which are hereby incorporated by reference herein. ICW notifies subscribers who are connected to the Internet by way of a dial-up connection of incoming telephone calls directed to their telephone line by way of the internet. Calls to an unavailable subscriber are initially forwarded to a separate ICW server by the CO via the CFBL feature, and are subsequently forwarded to the subscriber""s VMS if the subscriber is not in fact connected to the internet, or if disposed of by the subscriber. Other intermediate services may include wireless pager notification of an incoming call; cellular network call notification of an incoming call to a cellular telephone; or xe2x80x9csingle number servicexe2x80x9d that forwards calls to one of a list of alternative DNs to notify the subscriber of an incoming call.
However, as incoming calls are typically transferred to an intermediate server and then to a VMS, failure of a conventional intermediate server impacts the provision of intermediate services and additionally adversely impacts the reliability of VMS service. As subscriber-specific VMS information typically resides solely on the single intermediate server assigned to a subscriber, proper VMS call forwarding becomes impossible when the server becomes unavailable. The CO is only able to connect the caller with the busy signal. Disadvantageously, then, the failure of the intermediate server prevents the caller from being able to leave a voice message, even though the VMS may be fully operational.
Similarly, the provision of intermediate services in this manner prevents a caller from receiving intermediate service in the event that the single interconnected intermediate server fails or otherwise becomes unavailable. Disadvantageously, no provision for backup intermediate service exists.
Accordingly, the present invention attempts to provide an arrangement of intermediate servers to overcome some of the disadvantages of known intermediate server arrangements.
It is an object of this invention to provide a method and device that improves the reliability of network call handling systems.
Advantageously, the method and device may also provide backup intermediate service through the use of alternate intermediate servers.
In accordance with an aspect of the present invention there is provided a method of operating first and second servers on a telephony network. Each of the first and second servers are operable to provide a subscribed telephony service in response to receiving incoming calls for specified subscribers prior to the incoming calls being processed at one or more additional call handling systems. The method includes: associating with the first server a first plurality of primary subscribers for whom the subscribed telephony service is to be provided by the first server; associating with the second server, a second plurality of primary subscribers for whom the subscribed telephony service is to be provided by the second server, the first plurality being different from the second plurality; receiving an incoming call for one of the first plurality of primary subscribers, at the first server; in response to the receiving an incoming call for the one of the first plurality of primary subscribers, providing the subscribed telephony service to the incoming call for one of the first plurality of primary subscribers at the first server; receiving an incoming call for one of the second plurality of primary subscribers, at the first server, in the event of unavailability of the second server; forwarding the incoming call for the one of the second plurality of primary subscribers from the first server to a downstream call handling system within the telephony network associated with the one of the second plurality of primary subscribers, thereby ensuring access to the downstream call handling system for calls for the second plurality of primary subscribers in the event of unavailability of the second server.
In accordance with another aspect of the present invention there is provided a method of operating a first server on a telephony network. The telephony network includes the first server and a second server, each operable to provide a subscribed telephony service in response to receiving incoming calls for specified subscribers prior to the incoming calls being processed at one or more additional call handling systems. The method includes: associating with the first server a first plurality of primary subscribers for whom the subscribed telephony service is to be provided by the first server; receiving an incoming call for one of the first plurality of primary subscribers, at the first server; in response to receiving the incoming call for the one of the first plurality if primary subscribers, providing the subscribed telephony service to the incoming call for the one of the first plurality of primary subscribers at the first server; receiving an incoming call for one of a second plurality of primary subscribers for whom the subscribed telephony service is provided by the second server, at the first server, in the even of unavailability of the seond server; in response to receiving the incoming call for the one of the second plurality of primary subscribers, forwarding the incoming call for the one of the second plurality of primary subscribers from the first server to a downstream call handling system within the telephony network associated with the one of the second plurality of primary subscribers, without providing the subscribed telephony service to the incoming call for the one of the second plurality of primary subscribers at the first server, thereby ensuring access to the downstream call handling system for calls for the second plurality of primary subscribers in the even of unavailability of the second server.